Märket ("The Mark", Swedish pronunciation: [ˈmærkə(t)]) is a small 3.3-hectare (8.2-acre) uninhabited skerry in the Baltic Sea between Sweden and Finland (in the area of the autonomous Åland Islands), which has been divided between two sovereignties since the Treaty of Fredrikshamn of 1809 defined the border between Sweden and the Russian Empire as going through the middle of the island. The westernmost land point of Finland is on Märket. The Finnish side of the island is part of the Municipality of Hammarland.